Compounds which modulate serotonergic receptors are known to have a therapeutic use in man for the treatment of anxiety, schizophrenia, depression, convulsions, migraine, insomnia, and other diseases of the central nervous system. Further, such ligands may be useful in treating cardiovascular disorders such as hypertension (e.g. J. Med. Chem, 1992, 35, 3058-3066). Partial agonists of the serotonin-1A (5-HT.sub.1A) receptor have been found to be useful for the treatment of anxiety; a compound of this type is buspirone, marketed as an anxiolytic (Med. Res. Rev, 1990, 10, 283-326; Annu. Rev. Med, 1990, 41,437-446). In addition, compounds modulating the 5-HT.sub.1A site may be useful as antiagressives or serenics (Drug News Perspect, 1990, 3, 261-271).
Compounds having some structural similarity to those of the present invention are described in European Patents 463691 and 485952, World Patents 9119719, 9304682, and 9304684 as well as Rao, V. A.; Jain, P. C.; Anand, N. Ind. J. Chem. 1969, 7, 833, Rao, V. A.; Jain, P. C.; Anand, N.; Srimal, R. C.; Dua, P. R. J. Med. Chem. 1970, 13, 516, Gupta, S. P.; Chatterjee, S. S.; Bindra, J. S.; Jain, P. C.; Anand, N. Ind. J. Chem. 1975, 13, 462, Kumar, N.; Jain, P. C.; Anand, N. Ind. J. Chem. 1979, 17B, 244, Huff, J. R.; King, S. W.; Saari, W. S.; Springer, J. P.; Martin, G. E.; Williams, M., J. Med. Chem. 1985, 28, 945; Russell, M. G. N.; Baker, R.; Billington, D. C.; Knight, A. K.; Middlemiss, D. N.; Noble, A. J. J. Med. Chem. 1992, 35, 2025.